The invention concerns a hammering screwdriver with a motor which transmits a rotating motion through a shaft to a screw spindle which drives a cam controller casing surrounded by a hammering mechanism cage for controlling the hammering motion, whereby a track arranged on the front of the cam controller casing facing away from the screw spindle is situated over its entire periphery which has an elevation in the axial direction through which the cam controller casing is arranged, yielding a channel for the rotation of a ball in interplay with the opposite-lying hammering mechanism cage, and whereby the cam controller casing engages in an axially displaceable pin which compresses a spring, ensuring a return to the initial state through a sliding motion exercising the hammering action.
Hammering screwdriver devices are used as an aid in tightening and loosening screws. They have become especially indispensable for minimizing the expenditure of time and energy in numerous technical areas. In contrast to traditional pneumatic or electrical screwdriving devices, hammering screwdrivers have the advantage that, in addition to high torque, strokes are executable in an axial direction with them. Chiefly three types of striking mechanisms have prevailed, the pin stroke mechanism, the hammer stroke mechanism and the claw stroke mechanism.
At the same time, it has proved to be a great disadvantage that it has thus far not been possible to regulate the torque in connection with tightening screws, or to restrict it controllably. Thus, it occurs again and again, as a consequence of excessively high momentum stress, that the screws are too tightly drawn in. This can lead to destruction of the screws or its thread, but also to that of the material into which the screws are inserted. Especially serious problems arise within the framework of installing automobile wheels. When the screws are subsequently loosened, however, a high applicable torque is once again desirable in connection with automobiles, especially through braking torque, for which the hammering action is indispensable. A screwdriving device which instead of a combined rotation/hammering action offers only a simple rotation action often does not suffice here. When using hammering screwdrivers, damage to the rims occurs repeatedly as a consequence of high torque. The consequences of this are imbalances which can lead to the rims being unusable in extreme cases. It is in any case necessary that the operating personnel check the seat themselves with a mechanical torque wrench after installing the screws. A further disadvantage in the previously known technology lies in that a high noise stress arises when the screws are overwound as a consequence of excessively large applied torques. Moreover, destruction, possibly of the thread, which can lead to devastating consequences with automobile wheels in particular, is thereby more difficult to determine.